Monday, April 2, 2012

Eocene Diet Follow-up

Now that WHS readers around the globe have adopted the Eocene Diet and are losing weight at an alarming rate, it's time to explain the post a little more. First, credit where credit is due: Melissa McEwen made a similar argument in her 2011 AHS talk, where she rolled out the "Cambrian Explosion Diet", which beats the Eocene Diet by about 470 million years. It was probably in the back of my head somewhere when I came up with the idea.

April Fools day is good for a laugh, but humor often has a grain of truth in it. In this case, the post was a jumping off point for discussing human evolution and what it has to say about the "optimal" human diet, if such a thing exists. Here's a preview: evolution is a continuous process that has shaped our ancestors' genomes for every generation since the beginning of life. It didn't end with the Paleolithic, in fact it accelerated, and most of us today carry meaningful adaptations to the Neolithic diet and lifestyle.

Modern genetics has revealed that we are all genetic patchwork quilts, our genomes shaped by several different environments, and perfectly adapted to none. We're caught in the middle of an evolutionary transition, partially adapted to Neolithic life but not quite there yet, and no longer quite adapted to the life of a hunter-gatherer either.

I'll delve into these topics further in upcoming posts, and introduce Ötzi, the Tyrolean ice man, who will be our guide.

42 comments:

I'm looking forward to reading more in this vein. Your's is an expertise people can come to trust quite easily because the soundness of your method is so readily apparent. I truly value and enjoy the fruits of your labors here. Thank you. I'm eagerly awaiting the next post.

I'm happy Otzi will be our guide! I read somewhere that he had a sacralized 5th lumbar vertebra, as do I, which could mean he's a distant ancestor. Don't tell me if it's not so because we all need our happy fantasies.

Anyhow, I'm excited about the teaser you've provided for the next series because I'm not good at extremes. Finding a sensible way to respect both our evolution and our recent adaptations just feels "right" and I can't wait to read your articles. Thanks!

It's a pity that the "evolution ended with the Paleolithic" line is so popular in the paleosphere. Mark Sisson makes much of it in The Primal Blueprint. The idea that evolution ever stops should be nonsense to anyone with a high school grasp of evolution. It really undermines the paleo diet's credibility.

I'm by no means an expert on evolution, so correct me if I'm missing something, but doesn't evolution fundamentally require some degree of selection? This would suggest that once civilization reached a point where essentially everyone reached the age of reproduction (and subsequently reproduced) that natural selection would cease to exist (in humans). Although we may have different epigenetic responses to our environments, and there may be small variations among all of us, traditional evolution seems to fall apart without competition.

IcedCoffee, evolution is first and foremost due to differential reproductive success, sexual selection is very live and well in modern society, and there are large individual differences in how many babies you manage to make before passing on. Someone with the unfortunate genetics to become hyperobese, infertile or develop severe illnesses in response to the modern (food) environment is probably less likely to have much success with the opposite sex.

Hmm no, I think if anything, fat people tend to settle down sooner and have more children. But that's a recent phenomenon (last 50 years). I would think constant low level famines in the middle ages and earlier would exert a much greater pressure as people needed to eek out every calorie from their grain based diets.

IcedCoffee, we haven't reached a point where everyone reaches reproductive age, at least not everywhere in the world. Furthermore, even in places where almost everyone does reach reproductive age, not all people reproduce, whether by choice or otherwise.

Having read every one of your posts since the inception of your blog and being a loyal supporter of your work, let me state for the record that the usage of the term "quilt" pretty much invalidates EVERYTHING you have ever written

Lactose digestion in adults, of course.Alcohol tolerance (both the ability to metabolise it and avoid addiction).Seafood is ridiculously healthy for humans - supposedly a creature that came from the savannah. So maybe a down-regulation of the ability to make EPA and DHA?Jacked up immune system. Pretty sure humans must have some of the best defences against infections (of any primate at least).The ability to eat pretty much anything - though that's probably a paleolithic trait.

As Colldén said, reproduction is crucial in evolutionary selection. The evolutionary process is continuing, even in humans. In Sweden I believe most females reproduce, but a fair amount of males never reproduce. Instead the more popular males are recycled.

Some interesting thoughts, but I'm not very persuaded that they amount to anything substantial. Most people reproduce, even those with less than stellar genotypes. At best sexual selection would suggest a split in society based on good genes and bad genes, but all of the genes would still be there. (and I doubt this will occur.)

And even if sexual selection is an issue (and has been for the past 10,000 years), it would favor those with a greater propensity for reproduction, not necessarily for survival. Most people reach the age of reproduction, so then its just a question of who actually does, and how much, neither or which probably relate to diet/nutrition in any substantial way.

In my mind most of the adaptations that (might have) emerged aren't really evolutionary changes in the human genome, but simply changes in gut flora responding to differing dietary stimuli. And this is assuming that we had to adapt at all to the consumption of these newer agricultural foods.

The percentage of people not reaching reproductive age was very substantial for the vast majority of the neolithic period.

In the relative peace and prosperity of Tudor England for example:

“Average life expectancy in the early sixteenth century was barely thirty, a figure determined largely by heart-breaking levels of infant mortality: 25% of children died before their first birthday, and 50% before their tenth.”- www.hrp.org.uk/Resources/Peter%20MarshallFINAL.pdf

Over 10,000 years, I think that's enough to bring about substantial changes. Just think about how quickly dog breeds can be utterly transformed over a few generations.

Nicholas, You raise a good point, although I have to wonder what the implications of it are (regarding diet).

My primary question would be, "what is the affect of diet on infant mortality?" In my mind, (aka opinion) the primary issue of the Neolithic age shifted from food to disease. So any change that might manifest in our DNA would be towards resistance to disease/infection (and not adaptability to diet).

This is not to say that a baby who, for instance, couldn't digest wheat wouldn't still be selected out, but it doesn't suggest that a heightened ability to digest wheat would warrant any particular advantage. (Whereas a heightened resistance to disease/infection probably would offer an advantage).

And I think its worth mentioning that infant mortality was not something new to the Neolithic age (obvious but important). I imagine this was a distinct breed of natural selection (focused on disease and infection) that probably did continue up until very recently.

And just as an aside, I would like to acknowledge that I totally agree that we as humans are still changing, I simply think that these changes are no longer manifesting as "adaption."

You're right, Stephan. Dr. Henry Harpending says the same thing and he is a top scientist in the field.

Only people trying to make money off of Paleolithic this and that do not acknowledge how we are NOT exactly like Paleolithic Man. As you pointed out we have evolved increasingly rapidly to new challenges.

I have learned so much in the last 6 years. I will never be swindled again by these Internet gurus selling people things.

Real scientists operate within the bounds of significant uncertainties with regard to human physiology etc. Salesmen are not bound by scientific rules. If the public were more scientifically, as Carl Sagan wanted, Internet guru charlatans would not have a market at all.

I think the ability to make the most of a particular food and resistance to disease and infection are bound up together. If the neolithic staples of bread and cheese cause problems for a neolithic child, such that their organs just aren't getting the all nutrients they need, or are sent haywire by toxins they can't deal with, then their ability to fight off disease and infection, and cope with periods of starvation, is going to be undermined, and they're going to less likely to make it to reproductive age.

Personally I think that "adaptation" is still a perfectly appropriate word for modern-day evolution. In the language of the theory of evolution, "adaptation" to an environment has only ever been measured by one yardstick - the extent to which a characteristic leads to reproduction. I think there's a tendency to link evolution with what we would regard as a moral, intellectual or physical improvement, but that's confusing human moral values with a valueless sequence of cause and effect, which is all that evolution is. If, hypothetically speaking, irresponsible people tend to have more children, and those children go on to have more children, then irresponsible people are, in evolutionary terms, better adapted to their environment.

Nicholas,I think we pretty much are in agreement on most of this, but I'd quibble over some details.

My primary concern would be that, although outright food intolerance (and similar conditions) would surely be tied with disease, I think simply not having these problems would be sufficient.

My point was primarily that I get the impression that many people view evolution in terms of: "we have been exposed to x for y years, therefore we have adapted to it," which is a flawed assumption. Not to mention the entire idea that "we evolved eating it, there we SHOULD eat it" is scientifically unsound. Good for generating hypothesis, but not for basing arguments (but i digress).

I totally agree that evolution now is more geared towards whoever is the most likely to reproduce. I think that was the premise of that movie Idiocray; dumb people reproduce more than smart people, so smart people will go extinct in the future.

IcedCoffee: Yeah, I guess we pretty-much agree. By the way, since people tend to choose similarly intelligent/stupid partners, you could argue that we'll slowly evolve into increasingly stupid and increasingly clever sub-species of humanity. However, before that has time to play out I expect we'll just be genetically engineering super-humans or replacing everyone with robots.

Greenacres: Well a paleo diet still seems to be the safest policy, so it's not redundant. I think something like Chris Kresser's self-experimentation-based "paleo template" diet is the way forward.

Nicholas, Haha I actually thought about bringing up the divergent evolution idea earlier, but decided against it in case people called me overly simplistic. Although the idea is amusing: smart people breed with smart people = super smart people; fat people breed with fat people = super fat people. But yea if you believe Kurzweil we'll all be uber-enhanced with technology soon-ish anyways. Just gotta survive until then.

Seems to me very recently in 1st world countries, selective reproductive pressure with regards to food would be primarily the ability to eat a bunch of processed crap food and still remain fertile. Partners can usually be found (especially for females) eventually as long as you are capable of producing. Health after about 40 doesn't really matter hugely with regards to reproductive success, especially as community/family involvement practices lessen. But current selective pressure in other countries, like in the 3rd world, varies drastically by country. Each 'micro environment' varies drastically, but I think in the end, it is going more towards crap food for more and more people.

Agriculture allowed our culture to believe we are immune to the laws of nature. We are not. We cannot sustain this population in perpetuity. Natural selection is waiting in the wings. Remove farming and agriculture based cultures from the picture and you see a world and our bodies in balance.

@Todd,Interesting study, I wish I could view the entire article. Although I wouldn't call myself an anti-pufa person necessarily, I do have a few thoughts:

My biggest interest is actually the use of butter as their saturated fatty acid. Butterfat is relatively high in short and medium chain fatty acids, which are metabolized directly into the liver. Couple that with a group of people who are "abdominally obese" (aka probably hyperinsulinemic) and it seems like we have a recipe for putting fats into the liver and not letting them get out.

Also their comparison of "compliant subjects" immediately raised my skepticism alert, although without seeing more of the study I can't really comment.

Also the choice to maintain their macronutrient ratio makes me want to know what else they were being fed.

Nonetheless, this will definitely give me pause next time someone asks me if butter is better than veg oil.

a proper diet program is good for our body systems. in many terms human does not give much importance to their body and food. its a self killing process. some decease related to food and bad lifestyle we can face many health issues. heart failure, heart attack and Heart Transplantation are critical problems. we must take good care of our health and body.

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I'm an obesity researcher, neurobiologist, and author. In addition to my research, I enjoy synthesizing and communicating science for a general audience. I have a BS in biochemistry (University of Virginia) and a PhD in neurobiology (University of Washington).
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